Interlock contact mechanism



Dec. 22, 1959 c. F. BRAUNECK INTERLocK CONTACT MECHANISM Filed Sept. 30, 1957 INVENTOR.

6IIARLI Il IRA UNICI( l ATTORNEY 2,918,554 INrEvnLocK 4counter,ivrEcnANIsM Charles'iF. Brauneck., Glen Cove,' N.Y., assignor to Mur- ,ray Manufacturing Corporation, Brooklyn,

,This invention relates tointerlock contact. mechanisms,

yand particularly to suchy mechanisms which are luseful in electromagnetic motor starter arrangements.

More specifically, this invention relates to a contact mechanism which may be easily mounted to an electro- 'rnagnetic switch of rthe motor starter arrangement.`

The purpose of the contact mechanism-'is to provide an electric-al holding interlock for the electromagnet of the switch. Electrically operated switches or magnetic motor starters'are usually operated by closing a normallyopen, momentary contact device, li.e. a push button station. Closingthe momentary contact completes a voltage supply circuit to th'e electromagnet. Upon releasing the momentary contact the energizing circuit therethrough is interrupted; However, the'contact mechanism being connected across ythis momentary contact device and operated by the electrr-rnagnet maintains the voltage supply to the electromagnet after the -push button contact is released. The 'electromagnetfv circuit may be opened by openngnormally closed contacts connected in series with the voltage supply. vAnother purpose of the contact mechanism is to provideK4 contacts `V for an'alar'm circuit, and frorelectrically interlockingother electromagnetic devices with the operation'of theclectromagnetic switch.

` Inorder to operate an electromagnetic switch, atleast .one normally open contact mechanism is required fora holding interlock. However, :there are instances when asf many as four 'contact-mechanisms are required.

' The known contact mechanisms are of a construction which does not lend itself to multiple contact assemblies. To construct, for example, an assembly of four contact mechanisms,special operating members and custom fab-- rication `would be required. `Moreover the known con-` structions are generallysuited toiaarticular switch, and for different size switches, separate contact mechanisms arc required.

Accordingly,y it is an object of this invention to provide one standard interlock contactl mechanism having both normally opened andnormaliy closed contacts for most sizjes of known electromagnetic switches.

' lt isa' further object of this invention to provide a contact mechanism whichis extremely simple in construction and whichis capable of interlocking more devices than v is possiblewith the known mechanisms.

It is a feature of my invention-to `provide such a con- I tact mechanism which may easily be mounted by two United States Patent C) ice By way of example, the contacts may be connected across the push button contact described above. An armature carrying a bridging contact is movably mounted within the housing, the bridging contact being adapted to'engage and shunt the spaced contactsat a given position of the armature. The armature comprises means on one side thereof for receiving an external force to actuate the' armature is normally in a first position, whereinone ofl the bridging contacts engages one pair of spaced icontacts while the other bridging contact is separated from thc other pair of spaced contacts. Actuation of the armature moves the bridging contacts to reverse the condition of the spaced contacts.

The above-mentioned and'other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, vtherein:

Fig. 1 is a cross-sectional view of the contact mechanism with one half of the cover removed;

Fig. 2 is a cross-sectional view of the mechanism taken along lines 2-2 of Fig. 1; and

Fig. 3 is an end view of two contact mechanismsshown in cross-section and mounted side-by-side to an electromagnetic switch.

Referring now to Figs. l and 2, the contact mechanism comprises an insulator housing made essentially in two parts, 1, 2. The housing is made preferably of an insuiating material which may be molded by mass production techniques.

The contact mechanism comprises two pairs of spaced contacts 3, 4 and S, 6 respectively. By way of example, the contacts 5 and 6 may be connected across the push button contact mentioned above and the contacts 3 and- 4 may be connected in an alarm circuit to indicate the condition of the switch. The contacts are provided with wire connectors 7, 8, 9 and 10 for connection with the wires of the associated circuits (not shown).

The contacts are so disposed that one pair 3, 4 may be considered as positioned at two adjacent corners respectively of a rectangle, and the contacts 5, 6 as positioned at the two opposite corners of the rectangle.

The contacts are selectively closed or opened by an armature 11 carrying a pair of bridging contacts 12 and 13. The armature 11 is made of insulating material and is slidably mounted in a groove 14 formed in the sides of the housing. The armature carries the pair of bridging contacts 12, 13 in a centrally located slot 15. A spring 16 is mounted in the slot 15 and urges the bridging contacts 12, 13 against the opposite ends of the lslot as shown. The spring is preferably maintained in position by depressions formed on the bearing surface of the bridging contacts.

The distance between the bridging contacts is less than the distance between the respective pairs of spaced contacts, whereby only one pair of spaced contacts can be closed at a time.

A spring 17, positioned in a groove 18, is provided between an end 19 of the armature and a terminating wall 2) of the groove 18. The spring 17 is maintained in position by an extension 21 provided at the end 19 of the armature. The normal action of the spring 17 urges the armature upwardly, as shown, until the bridging contact 12 engages the pair of spaced contacts 3, 4. The contact between the bridging contact and the spaced contacts is under tension as a result of the spring 16 bearing against the bridging contacts.

The armature is moved by the application of a suitable force on a lug or extension 22 extending from the armature. The lug is positioned in a slot 23 in the housing and projects a given distance beyond the wall 2 thereof. The dimensions of the slot 23 are selected to permit the lug to have a predetermined amount of lon-A gitudinal movement. The portion of the lug 22 projecting from the housing is adapted to receive the actuating force.

On the opposite side of the armature, a second lug 24 is provided offset relative to the first lug 22 by approximately the height of the lug 22. The second lug 24 is slidable in a slot 25 which is similar to the slot 23.

The lugs 22 and 24 are preferably, although not necessarily, molded integrally with the armature 11.

Although any suitable means may be provided for operating the armature by applying a suitable force to the lug 22, l have shown by way of example an electromagnetic switch for performing this function. Referring now to Fig. 3, two similar contact mechanisms are shown mounted to an electromagnetic switch 26. The contact mechanisms are mounted side-by-side and attached to the electromagnetic switch simply by two screws (not shown) passing through holes 28 in both mechanisms and threaded into the switch housing. Since the particular type of electromagnetic switch forms no part of this invention, I have shown only the structure necessary for an understanding ot the invention. The switch 26 comprises an armature 29 to which a driving arm 30 is attached. The contact mechanism adjacent the switch is mounted so that the lug 22 extends into a slot 31 in the switch housing and in the path of the driving arm. Since the length of armature travel in the contact mechanism is limited by the distance between the bridging contact 13 and the pair of spaced contacts 5, 6, the contact mechanism must be mounted to the switch housing so that the driving arm 30 does not exceed this distance while bearing on the lug 22. As shown, the driving arm 30 passes through a certain pre-travel distance before contacting the lug 22.

A second contact mechanism is mounted ush against the first mechanism with the projecting lug 22 of the second mechanism contacting the lower face of the lug 24. Thus` when the armature of the first mechanism is driven by the driving arm 30 of the switch, the force is transferred to the second armature by means of the lug 24 acting on the projecting lug 22 of the second armature.

As mentioned above, additional contact mechanisms may be mounted, the number being limited only by the strength of the electromagnet to handle the additional operating forces.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims.

What I claim is:

1. A contact mechanism, comprising a housing, a first pair of spaced contacts mounted in said housing, an armature movably mounted in said housing, a first bridging contact mounted on said armature and positioned to engage said pair of spaced contacts at a first predetermined position of said armature, a lug extending from said armature through a slot in said housing beyond the wall thereof for receiving an external force to actuate said armature into said predetermined position and a second means on another side of said armature responsive to the movement of said armature for delivering a force to a second contact mechanism.

2. The mechanism according to claim l and further comprising a second pair of'spaced contacts mounted in said housing parallel to said first pair, a second bridging contact mounted on said armature parallel to said first bridging contact. said first and second Vbridging contacts being positioned between the respective pairs of spaced contacts, and means normally urging said armature into a second predetermined position whereby said second bridging contact engages said second pair of spaced contacts.

3. VThe mechanism according to claim 1,jwherein said second means comprises a lug extending from an yopposite side of said armature and positioned in a slot in said housing.

4. A plurality of contact mechanisms adapted to be operated by an electromagnetic switch, comprising means rigidly attaching said mechanisms sidebyside to said switch, each of said mechanisms comprising an insulator housing. first and second pairs of spaced contacts mounted in said housing, thc contacts being located so that the contacts of one pair define two adjacent corners of a rectangle and the cont..cts of the other pair define the opposite corners of the rectangle, an armature movably and symmetrically mounted between the contacts of the respective pairs, a pair of bridging contacts mounted in a slot in said armature parallel to and between said pairs of spaced contacts, a first spring mounted in said slot urging said bridging contacts against the opposite ends of thc slot, the distance between the bridging contacts being less than the distance between the respective pairs of said spaced contacts wnereby only one pair of said spaced contacts may be closed at a time by said bridging contacts, a.second spring positioned to urgesad armature into a position wherein one of said bridging contacts normally engages one of said pairs of spaced contacts, a pair of lugs on opposite sides of said armature, both of said lugs extending respectively through slots in the opposite sides of said housing and one of said lugs projecting beyond the side of said housing, said electromagnetic switch comprising a movable driving member, said one lug being disposed Vin the path of said driving member, whereby the armature is actuated by the force appied to said one lug bv said driving member. the effective travel of said driving member being slightly more than the separation between the other of said bridging contacts and the adjacent pair of spaced contacts, whereby when said armature is fully actuated said other bridging contact is resiliently urged against the adjacent spaced contacts, and said plurality of contact mechanisms being mounted so that the projecting lug from one mechanism is disposed in the slot for and in the path of the nonprojecting lug of an adjacent mechanism, whereby the driving arm controls the operation of a plurality of armatures through said lugs.

References Cited in the file of this patent UNITED STATES PATENTS 2,532,305 Heller Dec. 5, 1950 2,585,824 Noyes Feb. 12, 1952 2,841,661 Wintle July l, 1958 

